Solar eclipse

About: Solar eclipse is a research topic. Over the lifetime, 2737 publications have been published within this topic receiving 22625 citations.

Short-period intensity oscillations in the solar corona observed during the total solar eclipse of 26 February 1998

Abstract: Encouraged by the detection of high-frequency, low-amplitude continuum intensity oscillations in the solar corona during the total solar eclipse of 1995, we designed and fabricated a six-channel photometer incorporating low-noise Hamamatsu R647 photomultipliers Fast photometry at five different locations in the solar corona was performed at Don Bosco Mission, Venezuela during the total solar eclipse of 26 February 1998 Three interference filters with passbands of about 150 A and centered around 4700, 4900, and 5000 A were used The photometric data were recorded at a rate of 20 Hz in three channels and 50 Hz in the remaining three channels The power spectrum analysis of one of the channels that recorded appreciable counts indicates the existence of intensity oscillations in the frequency range 001–02 Hz A least-squares analysis yields 901, 252, and 69 s periods for the three prominent components which have amplitudes in the range 05–35% of the coronal brightness These periods and their amplitudes are similar to those detected in the coronal intensity oscillations during the 1995 eclipse

Observations and discussions concerning high polarization features in the solar corona.

Abstract: Photographic observations were obtained of the radial and tangential polarization of the solar corona for the 1970, March 7, solar eclipse The corona was photographed using a neutral density filter and rotating linear polaroid sectors to allow the polarization structure to be seen from 1 to 6 solar radii Anomalously high polarizations were found for structures with the E-tangential intensity being predominantly larger than the E-radial intensity These structures are generally filamentary in nature and radial in direction One case with a high radial polarization was also found The photographs were calibrated accurately against the Earth shine from the Moon Possible source mechanisms are discussed that may explain this new component in the solar corona Most sources may be ruled out on physical grounds One possibility appears to be synchrotron radiation from 10 GeV electrons in a 04 G field The existence of these electrons, however, is unlikely in that spacecraft observations at 1 AU do not confirm their presence

First Global-Scale Synoptic Imaging of Solar Eclipse Effects in the Thermosphere

Abstract: A total solar eclipse occurred in the Southern Hemisphere on 2 July 2019 from approximately 17 to 22 UT. Its effect in the thermosphere over South America was imaged from geostationary orbit by NASA's Global-scale Observation of Limb and Disk (GOLD) instrument. GOLD observed a large brightness reduction (>80% around totality) in OI 135.6 nm and N2 LBH band emissions compared to baseline measurements made 2 days prior. In addition, a significant enhancement (with respect to the baseline) in the ΣO/N2 column density ratio (~80%) was observed within the eclipse's totality. This enhancement suggests that the eclipse induced compositional changes in the thermosphere. After the eclipse passed, a slight enhancement in ΣO/N2 column density ratio (~7%) was also seen around the totality path when compared to measurements before the eclipse. These observations are the first synoptic imaging measurements of an eclipse's thermospheric effects with the potential to drastically improve and test our understanding of how the thermosphere responds to rapid, localized changes in solar short wavelength radiation.

Ground-based observation of emission lines from the corona of a red-dwarf star

Abstract: All 'solar-like' stars are surrounded by coronae, which contain magnetically confined plasma at temperatures above 106 K. (Until now, only the Sun's corona could be observed in the optical-as a shimmering envelope during a total solar eclipse.) As the underlying stellar 'surfaces'-the photospheres-are much cooler, some non-radiative process must be responsible for heating the coronae. The heating mechanism is generally thought to be magnetic in origin, but is not yet understood even for the case of the Sun. Ultraviolet emission lines first led to the discovery of the enormous temperature of the Sun's corona, but thermal emission from the coronae of other stars has hitherto been detectable only from space, at X-ray wavelengths. Here we report the detection of emission from highly ionized iron (Fe XIII at 3,388.1 A) in the corona of the red-dwarf star CN Leonis, using a ground-based telescope. The X-ray flux inferred from our data is consistent with previously measured X-ray fluxes, and the non-thermal line width of 18.4 km s-1 indicates great similarities between solar and stellar coronal heating mechanisms. The accessibility and spectral resolution (45,000) of the ground-based instrument are much better than those of X-ray satellites, so a new window to the study of stellar coronae has been opened.